x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
log2(3) Library Functions Manual log2(3)
NAME
log2, log2f, log2l - base-2 logarithmic function
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <math.h>
double log2(double x);
float log2f(float x);
long double log2l(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
log2(), log2f(), log2l():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
DESCRIPTION
These functions return the base 2 logarithm of x.
RETURN VALUE
On success, these functions return the base 2 logarithm of x.
For special cases, including where x is 0, 1, negative, infinity, or
NaN, see log(3).
ERRORS
See math_error(7) for information on how to determine whether an error
has occurred when calling these functions.
For a discussion of the errors that can occur for these functions, see
log(3).
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
+--------------------------------------------+---------------+---------+
|Interface | Attribute | Value |
+--------------------------------------------+---------------+---------+
|log2(), log2f(), log2l() | Thread safety | MT-Safe |
+--------------------------------------------+---------------+---------+
STANDARDS
C11, POSIX.1-2008.
HISTORY
glibc 2.1. C99, POSIX.1-2001.
The variant returning double also conforms to SVr4, 4.3BSD.
SEE ALSO
cbrt(3), clog2(3), log(3), log10(3), sqrt(3)
Linux man-pages 6.04 2023-03-30 log2(3)
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